Figure 1. Conceptual models of AD genetic risk, dementia, and hearing loss motivating analysis.

Genetic variants known to increase Alzheimer disease (AD) risk can be used to distinguish between mechanisms that may explain the previously documented association between hearing loss and dementia risk. If incipient neurodegeneration or other shared etiologies influence hearing loss, it implies that genetic variants that increase the risk of dementia will also be associated with increased risk of hearing loss (A). If hearing loss has effects on biological or social processes that increase risk of dementia, it implies that genetic risk for AD will be independent of (not associated with) hearing loss (B) but that genetic risk for hearing impairment will be associated with risk of dementia.